public class Computer {
    public void powerOn(){
        System.out.println("打开笔记本电脑");

    }
    public void powerOff(){
        System.out.println("关闭笔记本电脑");
    }
    public void useDevice(Usb usb){
        usb.openDevice();

        if(usb instanceof Mouse){
            ((Mouse) usb).click();//写法不一样而已
           Mouse mouse = new Mouse();
           mouse.click();
        } else if (usb instanceof Keyboard) {
            Keyboard keyboard = (Keyboard) usb;
            keyboard.inPut();
        }
usb.cloceDevice();
    }
}
